Worried Husband

Hi, I'm new to all of this so please bare with me, my worry is with my wife and the problem she is having, it seem like every time she eats a little while later she has to go to the bathroom. However, this has long been going on long and just started about a month ago, and where my next though may sound strange, but she hasn't had her period and we believed that she was expecting, (although a store bought test said no) but was wondering could being pregnant cause the other symptoms? Please any info would be very appreciated.